Benchmark: Spread operator vs. Array.map and lodash.set

HTML Preparation code:


<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>

Script Preparation code:

permutations = new Array(10000).map(() => ({ pagination: 'blah blah blah' }));
function updatePagination(action, prev) {
  return action;
}
action = 'something else';
state = { data: { permutations: [] } };
index = 5;

Tests:

Spread operator
const updated = Object.assign([...permutations], { [index]: Object.assign({}, permutations[index], { pagination: updatePagination(action, permutations[index]) }) }) return { ...state, data: { ...state.data, permutations: updated } };
Spread operator v2
const updated = Object.assign([...permutations], { [index]: { ...permutations[index], pagination: updatePagination(action, permutations[index]) } }) return { ...state, data: { ...state.data, permutations: updated } };

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Spread operator
Spread operator v2

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/129.0.0.0 Safari/537.36

Browser/OS: Chrome 129 on Windows

View result in a separate tab

Test name	Executions per second
Spread operator	75015.3 Ops/sec
Spread operator v2	79680.3 Ops/sec

Autogenerated LLM Summary (model gemma2:9b, generated one year ago):

LLMs can make mistakes. Check important info.

This benchmark compares different approaches to updating an object within a larger array.

Let's break down the scenarios:

* **Scenario:** You have an array of objects (`permutations`) and need to modify a specific object at a given index (`index`).  The modification involves changing the `pagination` property.

**Test Cases:**

1. **"Spread operator"**: This test case uses the spread syntax (`...`) to create a new array. It assigns a newly constructed object (with updated `pagination`) at the specified index within this new array. The result is then merged back into the original state object.  
    * **Pros:** Can be concise and readable.
2. **"Spread operator v2"**: This test case also uses the spread syntax but assigns a modified version of the existing object directly to the new array. 
    * **Pros:** Similar conciseness and readability as the first approach.

**Libraries Used:**

*  **Lodash:** While not directly used in these tests, lodash is mentioned in the HTML preparation code. Lodash is a library commonly used for utility functions in JavaScript, including those related to object manipulation. It's possible the original benchmark intent included comparing lodash's `set` method against the spread syntax approaches.

**Considerations:**

* **Performance:**  The benchmark aims to measure the execution speed of these different techniques. Spread syntax is generally efficient for array manipulations, but its performance compared to other methods (like `map`) can vary depending on the size and complexity of your data.
* **Readability:** Both spread syntax approaches are considered fairly readable. The choice between them might come down to personal preference or the specific context of your code.

**Alternatives:**

1. **`Array.map()`**: 
    * You could iterate through the array using `map()` and update the object at the desired index within the mapped array. This approach often provides good control over the modification process.

2. **Original Object Modification (if mutable):** 
   * If your objects are mutable, you might directly modify the `pagination` property of the existing object within the array. However, this can have implications for immutability and potential side effects in larger applications.

Let me know if you'd like a deeper dive into any specific aspect!

Related benchmarks:

Spread operator vs. Array.map and lodash.set (version: 3)

A comparison of the performance of the spread operator, [ ...array ], vs. Array.map(i => ...) and

Comparing performance of: Spread operator vs Spread operator v2

Created: 8 years ago by: Registered User

Jump to the latest result

Spread operator

Spread operator v2

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gemma2:9b, generated one year ago):